High sensitivity detection of targets and in particular of biomarkers has been a challenge in the field of biological molecule analysis, in particular when aimed at detection of a plurality of targets and/or at detection of a target of a certain dimension or present in the sample at a low concentration. Whether for pathological examination or for fundamental biology studies, several methods are commonly used for the detection of various classes of biomaterials and biomolecules.
Some of the techniques most commonly used in the laboratory for detection of single biological targets include gel electrophoresis, polyacrylamide gel electrophoresis (PAGE), western blots, fluorescent in situ hybridization (FISH), fluorescence activated cell sorting (FACS), polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA). These methods have provided the ability to detect one or more biomarkers in biological samples such as serum and tissues and are also suitable for diagnostic purposes.
Subsequent polynucleotide encoding approaches provided improvements over previous techniques, and in particular, allowed performance of a highly sensitive and selective multiplexed detection of targets.